1. Field of the Invention:
The invention of this disclosure generally relates to attachment hardware useful for supporting a door of a cabinet. More precisely, this invention relates to improved pocket door attachment fittings providing affixed support posts which slide in a recessed guide track to allow the slidable opening and closing of the door of a cabinet.
2. Description of the Prior Art:
Slidable pocket doors typically do not have traditional pivotal hinges, but instead generally utilize posts or wheels affixed to the edges of the door, and riding in guide tracks. This system of posts or wheels in combination with guide tracks allows the door to be slidably retracted into an interior space, such as the interior of a cabinet where the door parallels the sidewall of the cabinet, leaving generally only the thin edge of the door showing through the open front of the cabinet. Pocket doors are employed where it is desirable to generally conceal the doors when in the open position, such as with display cases, stereo cabinets, and kitchen countertop appliance garages for example, where a certain aesthetic appearance may be desired. Pocket or retractable doors also conserve space directly in front of the cabinet, which may be useful in areas where space is limited. Furthermore, post and guide track door mounting hardware may be completely concealed with the door in the closed position, making for a more attractive overall cabinet.
Retractable pocket doors mounted in wooden cabinets which utilize posts have traditionally used four posts, two posts affixed to one edge of the door, and two posts affixed to the oppositely disposed edge of the door. The posts slide in recessed guide tracks, one guide track on each interior side of the cabinet adjacent each set of posts. Guide track generally consists of an open U-shaped channel formed into an L-shaped track member. Guide tracks are normally recessed into the floor and ceiling of a cabinet, or the two oppositely disposed sidewalls of a cabinet, positioned with one leg of the L-shaped track to the front of the cabinet, and the remaining portion of the L-shaped track extending toward the rear of the cabinet.
The majority of the past art pocket door support posts have been affixed to the door panels as separate units, each post being recessed into a separately drilled hole on the edge of the door. The independent affixment of the posts has several major disadvantages, one being the weakening of the door panel in the specific area of the drilled aperture. Cabinet door panels are generally quite thin, normally being 1/2 to 3/4 inches thick, and the drilling of a hole in the edge leaves a relatively thin layer of material on either side of the hole for supporting the post. This is especially significant when the door is manufactured of compressed chip board or plywood, sometimes leading to a fracture or failure of the wood on the side of the posts if stresses are applied to the door.
Another disadvantage of the individually affixed posts is that extreme care must be taken to precisely locate each post in relation to one another and also to the posts on the oppositely disposed edge of the door panel, otherwise binding of the door may occur during operation. A significant amount of time is also required to measure, drill and affix individual posts in this manner, which adds significantly to manufacturing costs even if templates or jigs are used for marking the holes to be drilled. A further disadvantage of individually installed posts is that the door cannot be easily removed or disconnected without causing major damage to the cabinet, since the posts are typically not accessible or removable once the entire cabinet is assembled.
A past art patent search was conducted at the U.S. Patent and Trademark Office to examine door attachment fittings similar to my invention. Of those patents examined, the following are considered most relevant:
J. M. Lewis et al were granted U.S. Pat. No. 4,727,680, on Mar. 1, 1988, for "Door Assembly For Cabinets Or The Like". The Lewis device concerns a door assembly for a "floppy disc" drive unit of a computer. This door assembly uses stationary posts affixed to the door panel which are guided within channels in the computer housing. Although not specifically illustrated, the stationary posts appear to be inherent to the plastic door panel itself. Incorporating the posts inherently into the door panel conserves time in assembly, but this method is not practical when used with wood. Wooden door panels having inherent wooden posts would not be strong enough, especially if constructed of particle board, and the manufacturing time of each door panel would be substantially increased. Furthermore, wooden doors are not plastic injection molded as is most likely the case with the Lewis device.
Another pertinent patent was issued to H. V. Steuernagel on Oct. 27, 1914, U.S. Pat. No. 1,115,345 for a "Swinging Structure Mount". Steuernagel discloses a structure with posts which are housed within grooves incorporated into the supporting body, providing an upward opening door. The posts of Steuernagel's device are apparently individually installed into the door panel. As previously stated, individual posts provide a relatively weak support structure in wood, and further require a great deal of time to install, which can be a major consideration in large scale assembly-line cabinetry construction where speed is crucial to keeping the cost of manufacturing low.
Other patents examined which were not directly relevant to my invention in that they utilized pivotal wheels or rollers instead of stationary posts, included U. S. Pat. Nos. 1,008,266, 1,223,697, 4,089,135, and a British patent, number 374,798. Rollers and wheels used in pocket door mountings generally take a greater amount of space for efficient operation than do stationary posts, and therefore are generally not suitable for wooden cabinetry where space is limited. Furthermore, roller and wheel assemblies are relatively costly to manufacture, and often need replacement due to wear of the moving parts every few years, otherwise binding and jamming will occur in the door during operation. Additionally, upward facing U-shaped guide tracks often collect dirt in the bottom interior, and since wheels or rollers roll directly on the bottom surface of the track, and they can not push the dirt out of the upward facing U of the track, collected dirt can adversely effect the operation of the wheels or rollers.